Plastic sealing method and apparatus



Feb. 28, 1967 G. vMARKUQ, 3,306,328

PLASTIC SEALING METHOD AND APPARATUS Filed March 25, 1965 2 Sheets-Sheet2 IN VEN TOR 650/965 19/4 F/(Z/S Y BYm( 2g United States Patent3,306,328 PLASTIC SEALING METHOD AND APPARATUS George Markus, WestOrange, N.J., assignor to Evans- Aristocrat Industries, Inc., Elizabeth,N.J., a corporation of New Jersey Filed Mar. 25, 1965, Ser. No. 442,66011 Claims. (Cl. 15038) This invention relates to a method ofmanufacturing articles such as wallets, passcases, and billfolds, and tothe resultant product, made out of thermoplastic sheet material. Moreparticularly, this invention is concerned with providing folded overedges by heat sealing wherein the obverse, outer surface of the assemblyis unmarred and unblemished.

Such articles have previously been made of blanks which have beenstamped out of plastic sheet material, and then folded up. Such blankscan be scored and sealed by high frequency current and mechanicalpressure, as shown in U.S. 2,631,646, granted March 17, 1953, to J. P.Gannon et al. An upper, long hem can be folded over and sewn, as shownin U.S. 2,746,503, granted May 22, 1956, to S. Knee. A side can befolded over other layers and cemented, as shown in U.S. 2,876,819,granted March 10, 1959, to H. Cohen et al.

Sewing is a time consuming process and the needle and thread must passentirely through the layers being sewn. The stitching is visible fromboth sides of the sewn-together assembly. Cementing is also timeconsuming, and since most thick layers of plastic, such as are used insuch articles, are non-porous, most cements do not adheresatisfactorily.

It is, therefore, an object of this invention to provide a method ofadhering folded-over layers which is both permanent, and not visible onthe obverse side of the assembly.

A feature of this invention is the provision of a method of heatingseveral layers of a multilayer assembly of thermoplastic sheet materialfrom one side of the assembly and limiting the depth or the number oflayers heated, so that at least the layer on the other side of theassembly is not significantly heated, and its outer surface is unmarred.

These and other objects and features of this invention will be morefully understood from the following description considered in connectionwith the accompanying drawings which are illustrations of the invention,where- 1n:

FIG. 1 is a top view of the main blank of the assembly before folding;

FIG. 2 is a top view of two blanks which are to be assembled to form aninsert for the assembly;

FIG. 3 is a top view of the two blanks of FIG. 2 assembled to form theinsert;

FIG. 4 is a perspective view of a detail of the main blank of FIG. 1before fol-ding;

FIG. 5 is a top view detail of the partially folded assembly showing themain blank and the insert;

FIG. 6 is a perspective view of the almost completely folded assembly;

FIG. 7 is a perspective view detail of a completely folded assembly;

FIG. 8 is a cross-sectional detail of FIG. 7, taken along the plane 8-8;and

FIG. 9 is a cross-sectional detail of FIG. 6, taken along the plane 99.

As shown in the drawing, the illustrative wallet is folded up from ablank. This blank may advantageously comprise a relatively soft, limpouter layer 10 of relatively heavy gauge, e.g. 18 gauge,polyvinylchloride, to simulate leather; and a relatively stiff innerlayer v12 of relatively light gauge, e.g. 11 gauge, polyvinylchloride,to

3,306,328 Patented Feb. 28, 1967 give the assembly stiffness. Anadditional, innermost layer of a limp, very thin gauge, e.g. 8 gauge,may be added to certain portions of the assembly to serve as adecorative liner.

The assembly blank may be formed with a peripheral tear-seal and scoredfold lines, by a suitable die, high frequency current and pressure, asshown in U.S. 2,631,646, supra.

The long, upper edge 14 of the main pocket of the wallet is formed byfolding over a marginal portion 16 of the blank onto the main or centralportion 18 of the blank to provide a hem. Previously the folded overportion was secured in place by sewing, as shown in U.S. 2,746,503,supra. Such a seam would be visible on both surfaces of the finishedwallet. If the hem were secured by the customary dielectric heat sealingtechnique, a capcitor/ pressure plate would be disposed on each outersurface of the hem, marring the outer surface of this assembled wallet.I have discovered that this marring may be avoided in either of twoways.

The first way is illustrated in FIG. 4. An incision 20 is made throughthe stiff layer 12, inwardly and parallel to a fold line 22, andperpendicular and up to the fold line 24 of the marginal portion 16. Anelongated metal plate 26 is inserted through the incision 20, betweenthe stiff layer 12 and the limp layer 10, and along the length of thefold line 24. Subsequently the marginal portion 16 is folded over itsfold line 24 and another metal plate, not shown, is placed over andpressed against the hem. A high frequency dielectric heater ofconventional construction, as shown in U.S. 2,631,646 is coupled to thetwo plates to heat the layers of thermoplastic material therebetween, toadhere them together. The layer 10 which is not between the two platesis not heated, and its outer surface is not marred. The inserted plate26 is now removed. It will be appreciated that when the side marginalportion 28 is subsequently folded over, the incision 20 will beconcealed.

The second way is by means of an ultrasonically operated tool; such as atool which is vibrated by a magnetostrictive driver. A tool which may beadvantageously used for this purpose is described in the periodical,Plastic Design & Processing, August 1962 under the title, NewDevelopment Advances Use of Ultrasonics for Automated Plastic FilmSealing, by H. Deans. The folded over hem is placed on an anvil and thetool is reciprocated against the hem. The vibration fuses the layers :byproducing a natural molecular bond. The depth of penetration of the weldis limited by means of a stop which permits the tool to penetrate intothe plastic to a predetermined depth while fusion is taking placebeneath the tool tip. This depth is set so that the lowermost layer isnot penetrated by the tool and thus its lower-outer surface is notmarred. The amount of energy necessary to raise the mass of the volumeto the fusion point is a function of the specific heat of the plasticinvolved. A large quantity of the ultrasonic energy is applied to theplastic in the form of heat, if the appropriate bonding conditions aresatisfied. This depends on the resiliency constant of the film itself,the coupling coefficient of the tool to the plastic, speed of the toolwith respect to plastic advance, if any, gauge of the film, and the rateat which the surface heat is carried away through the tool tip and theanvil.

An insert, such as a gusset 30 is assembled from a thin gauge blank 302of limp plastic and a heavy gauge blank 304. The heavy blank 304 mayhave transverse, parallel embossed indentations 306 therein to aid inthe ready bending of the blank when in use. The heavy blank 304 isdisposed on the light blank 306 as shown in FIG. 3, and fused thereto,as along two fusion lines or areas 308 and 310.

The insert 30 -is then fused to and between two tail portions 312 and318 of the main blank, as along two fusion lines or areas 320 and 324.

It will be appreciated that the main blank may be considered to comprisea central portion 18 and three marginal portions 16, 28 and 32. Thecentral portion 18 may be considered to comprise three subportions,which are the major distal portion 18 defined by the fold lines 22, 24,326 and 328, the two part major medial portion 330 plus 332 defined bythe fold lines 328 and 334, and the two part major distal portionprovided by the tail portions 312 and 318.

Subsequently, the blank is completely folded up, with any inserts, suchas the gusset 30 included, and the side marginal portion 28 and 32 arefolded over. The side marginal portion 28 is inserted through anincision 34. The assembly is placed over an anvil 36 and the tool 38 isdriven against the upper surface of the folded over marginal portion 28,as shown in FIG. 9, to fuse the portion 28 to the underlying layer 40,but not to fuse the lowermost layer, as previously discussed. The sidemarginal portion 32 is tucked between the upper two layers 332 and 318of the folded over blank. The assembly is placed over the anvil 36 andthe tool 38 is driven against the upper surface of the folded overmarginal portion 32, as shown in FIG. 8, to fuse the portion 32 to theunderlying layer 318, but not to fuse the lowermost layer, as previouslydiscussed.

The fused bonds thus provided form a permanent assembly which has anouter surface which is not marred.

It will be appreciated that the entire blank need not be comprised ofthe two layers and 12. The central or main portions, such as 18, areadvantageously comprised of both layers, wherein the layer 12 providesthe necessary stiffness. However, the marginal portions, such as 16,which are folded over need only be comprised of the layer 10, sincestiffness will be provided by the underlying main portion.

The wallet illustrated as embodying this inevntion is folded up from ablank having three major portions. The portion 18', together with theportion 40, the gusset 30, and the portion 332 form a full length,longitudinally open pocket or compartment which may be used to receivepaper currency. The portion 318 together with the portion 332, form ahalf length, laterally open sleeve or compartment which may be used toreceive an auxiliary passcase. This sleeve is open at both of itslaterals. It will be noted that the marginal portion is fused to theunderlying portion 318 and not to the overlying portion 332. The gusset30 is attached to the portion 318.

While there has been shown and described a presently preferredembodiment of the invention, it will be understood that various changesin the details of construction and in the form and arrangements of partsmay be made without departing from the underlying idea or principles ofthis invention within the scope of the appended claims.

What is claimed is:

1. A method of manufacturing an article of layers of thermoplasticmaterial comprising: forming a blank of two layers of said thermoplasticmaterial joined together; folding up said blank to at least in part formsaid article thereby having portions having a thickness of a number oflayers; heat fusing portions of a plurality of said number of layerstogether, said plurality being at least one fewer than said number.

2. A method of manufacturing an article of layers of thermoplasticmaterial comprising: forming a blank of two layers of said thermoplasticmaterial by heat fusing at least a portion of the peripheries of saidtwo layers together; folding up said blank to at least in part form saidarticle, said article thereby having portions having a thickness of anumber of layers; heat fusing portions of a plurality of said number oflayers together, said plurality being at least one fewer than saidnumber.

3. A method of manufacturing an article of layers of vil, and limitingthe travel of said tool into said resultant portion to a distance equalto a plurality of layers, said plurality being at least one fewer thansaid number.

4. A method of manufacturing an article of layers of thermoplasticmaterial comprising: forming a blank of at least two layers of saidthermoplastic material by heat fusing a peripheral tear-seal, thelowermost one of said layers serving as the outer layer of the finishedarticle; forming an opening in at least the uppermost one of saidlayers; inserting a first metal plate through said opening, above saidlowermost layer and below said uppermost layer; folding a marginalportion of said blank over said uppermost layer and said first metalplate; disposing a second metal plate over said folded over marginalportion and said first metal plate; coupling a dielectric heater to saidtwo plates to heat fuse the layers between said two plates; decouplingsaid heater and removing said plates.

5. An article of manufacture made of a blank of at least two layers ofthermoplastic material which have a peripheral tear-seal, wherein amarginal portion of said blank is folded over onto a major portion ofsaid blank, forming a resultant portion of a number of layers ofthickness, a plurality of said number of layers being heat fusedtogether, said plurality being at least one fewer than said number.

6. An article of the class described made up of a folded-up blank; saidblank comprising a first lower-outer layer and a second upper-innerlayer of thermoplastic material; said blank being divided into at leasta central portion and a marginal portion, wherein at least said centralportion is comprised of said first and second layers and said marginalportion is comprised of at least said first layer, the periphery of saidsecond layer being fused to the underlying first layers; said firstmarginal portion being folded over said central portion and fused to theunderlying central portion to a depth less than the total thickness ofsaid underlying central portion by at least the thickness of thelowermost first layer.

7. An article of the class described made up of a folded-up blank; saidblank comprising a first lower outer layer and a second upper-innerlayer of thermoplastic material; said blank being divided into at leasta central portion and a first and a second marginal portions, wherein atleast said central portion is comprised of said first and second layersand said first and second marginal portions are comprised of at leastsaid first layer, the periphery of said second layer being fused to theunderlying first layer; said first marginal portion being folded oversaid central portion and fused to the underlying central portion to adepth less than the total thickness of said underlying central portionby at least the thickness of the lowermost first layer; a firstsub-portion of said central portion being folded over another,underlying second sub-portion of said central portion; said secondmarginal portion being folded over said first sub-portion and fused tothe underlying central portion to a depth less than the total thicknessof said underlying central portion by at least the thickness of thelowermost first layer.

8. An article of the class described made up of a folded-up blank; saidblank comprising a first lower-outer layer and a second upper-innerlayer of thermoplastic material; said blank being divided into at leasta central portion and a first and a second marginal portions, wherein atleast said central portion is comprised of said first and second layersand said first and second marginal portions are comprised of at leastsaid first layer, the periphery of said second layer being fused to theunderlying first layer; said first marginal portion being folded oversaid central portion and fused to the underlying central portion to adepth less than the total thickness of said underlying central portionby at least the thickness of the lowermost first layer; an openingthrough said second layer of said central portion providing access tosaid lowermost first layer, adjacent said folded over first marginalportion; said second marginal portion being folded over said centralportion, covering said opening, and fused to the underlying centralportion to a depth less than the total thickness of said underlyingcentral portion by at least the thickness of the lowermost layer.

9. A wallet made up of a folded over blank having a first major distalportion, a second major medial portion, and a third major distalportion, to form a first and a second compartment; said firstcompartment having as side walls said first and third major portions,said second compartment having as side walls said third and second majorportions; said first major portion having a lateral marginal portionwhich is folded over said third major portion and under said secondmajor portion and is fused to said underlying third major portion.

10. A wallet made up of a blank having a first major distal portion, asecond major medial portion, and a third major distal portion folded upto form a first and a second compartment; said first compartment havingas side walls said first and third major portions, said secondcompartment having as side walls said third and second major portions;said first major portion having a first longitudinal marginal portionwhich is folded into said first compartment and is fused to said firstmajor portion along the length thereof; said first major portion havinga second lateral marginal portion which is folded over said third majorportion and under said second major portion and is fused to saidunderlying third major portion.

11. A wallet made up of a blank formed of two layers of thermoplasticmaterial having a first major distal portion, a second major medialportion and a third major distal portion folded up to form a first and asecond compartment; said first compartment having as side walls saidfirst and third major portions, said second compartment having as sidewalls said third and second major portions; said first major portionhaving a first longitudinal margin-a1 portion which is folded into saidfirst compartment and is fused to the inner layer of said first majorportion along the length thereof; said first major portion having asecond lateral marginal portion which is folded over said third majorportion and under said second major portion and is fused to saidunderlying third major portion.

References Cited by the Examiner UNITED STATES PATENTS 1,964,460 6/ 1934Gardner 38 2,631,646 3/1953 Gannon et a]. 156380 2,746,503 5/1956 Knee150-35 2,863,485 12/1958 Herbener 150-35 FRANKLIN T. GARRETT, PrimaryExaminer.

1. A METHOD OF MANUFACTURING AN ARTICLE OF LAYERS OF THERMOSPLASTICMATERIAL COMPRISING: FORMING A BLANK OF TWO LAYERS OF SAID THERMOPLASTICMATERIAL JOINED TOGETHER; FOLDING UP SAID BLANK TO AT LEAST IN PART FORMSAID ARTICLE THEREBY HAVING PORTIONS HAVING A THICKNESS OF A NUMBER OFLAYERS; HEAT FUSING PORTIONS OF A PLURALITY OF SAID NUMBER OF LAYERSTOGETHER, SAID PLURALITY BEING AT LEAST ONE FEWER THAN SAID NUMBER.